Pattern Select Switch Circuit: Description
WARNING: This page is about a different car, the 2007 Lexus GX 470. However, it is still accessible from the selected car via links, so may be relevant.
When 2nd start mode is selected with the pattern select switch, the ECM controls the solenoid valves and the transmission starts from 2nd gear.
In D position, the transmission automatically shifts up through 3rd to 5th as usual.
In 2nd position, the transmission is held in 2nd gear.